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INFORMATION SHEET ORDER NO.R5-2004-0028 9 INFORMATION SHEET ORDER NO.R5-2004-0028 10 CITY OF MANTECA,CITY OF LATHROP AND DUTRA FARMS CITY OF MANTECA,CITY OF LATHROP AND DUTRA FARMS WASTEWATER QUALITY CONTROL FACILITY WASTEWATER QUALITY CONTROL FACILITY SAN JOAQUIN COUNTY SAN JOAQUIN COUNTY Studies by the National Marine Fisheries Service,the U.S.Fish and Wildlife Service,the California With regard to groundwater,domestic wastewater contains constituents such as total dissolved solids Department of Fish and Game,the University of California at Davis,et.al.,have identified the Central (TDS),specific conductivity,pathogens,nitrates,organics,and metals. The Discharger's use of Valley Chinook Salmon and the Central Valley Steelhead as sensitive species that are affected by unlined ponds and the application of wastewater and sludge to land may result in an increase in the elevated temperatures in the San Joaquin River. There are four runs of salmon in the Central Valley concentration of these constituents in groundwater. Some degradation of groundwater by the that results in there being adults and juveniles in portions of the Delta every month of the year(Moyle, Discharger is consistent with Resolution 68-16 provided that: 2000). Generally,adults would be moving upstream in the fall,and fry and smolt moving downstream in the winter and spring. River temperatures above 68°F are unsuitable for supporting salmonoids a. The degradation is limited in extent; (Draft EIR,2000). Migration of adults is usually delayed when river temperatures reach this level. In b. The degradation after effective source control,treatment,and control is limited to waste a Department of Water Resources Study,adult salmon will cease migration if water temperatures are constituents typically encountered in municipal wastewater as specified in the above 70°F. At 77°F,adult mortality may occur(Myrick,Cech,2001). The Thermal Plan does not groundwater limitations in this Order; protect aquatic life from high temperature wastewater being discharged to an elevated temperature c. The Discharger minimizes the degradation by fully implementing,regularly river. However,the Thermal Plan limits incremental increases in temperature. Discharge from the maintaining,and optimally operating best practicable control technology(BPCT) wastewater treatment plant of treated effluent with an elevated temperature may affect salmon and measures;and other migrating fish in the San Joaquin River. In so far as elevated temperature is deleterious to d. The degradation does not result in water quality less than that prescribed in the Basin Chinook salmon,effluent temperature must be limited so as not to cause the receiving water to be Plan,e.g.,does not exceed water quality objectives. harmful to the salmon. When the assimilative capacity of the river is diminished,effluent temperature must be held to the water quality criteria. The CALFED Bay-Delta Program target is to maintain water The discharge to land authorized by this Order must comply with groundwater limitations,ground temperatures below 68°F in migratory routes of anadromous fish in the spring and fall(CALFED, water monitoring requirements and a schedule to evaluate whether the Discharger is implementing best 2000). This Order requires the Discharger to study the thermal impacts to the receiving water practicable treatment or control of the discharge. Compliance with this Order will result in use of best associated with a discharge of treated effluent with elevated temperatures. practicable treatment or control and will not further degrade the groundwater. 7 Antidegradation Analysis 8 Acute Toxicity The Regional Board must consider antidegradation pursuant to 40 CFR 131.12 and State Board Order No.97-115 prescribed stricter acute toxicity test procedures than the Discharger's previous Resolution No.68-16 and find that the permitted discharge is consistent with those provisions. permit. Specifically,the acute toxicity bioassay parameters were revised to require compliance with With regard to surface water,the receiving water may exceed applicable water quality objectives for the latest testing procedures contained in EPA/600/4-90/027F. The new USEPA procedure requires certain constituents as described in this Order. However,this Order requires the discharger,in the use of larval stage(0 to 14 days old)fathead minnows or golden shiners instead of the previous accordance with specified compliance schedules,to meet requirements that will result in the use of best method of using juveniles(15 to 30 days old). Larvae are much more sensitive to ammonia levels than the juvenile species. The new USEPA procedure for the acute bioassay test constitutes a more practicable treatment or control of the discharge and will result in compliance with water quality stringent acute toxicity limitation. This Order allows the Discharger to remove ammonia prior to objectives. Table 1 of the information sheet provides an analysis of the mass loading to the receiving conducting acute toxicity tests until I April 2004,when facilities are required to be operational to fully water for a number of constituents based on current operations and for an expanded discharge flow nitrify the wastewater. following plant upgrades. This Order requires compliance with technology-based standards and more stringent water quality-based standards. In developing effluent limitations,this Order allows the use of 9 Non-priority pollutants some of the assimilative capacity of the receiving water based on the current performance of the discharger and is consistent with the SIP. Where assimilative capacity is available in the receiving 9.1 Residual Chlorine water,this Order does not authorize the full use of the assimilative capacity. This Order is consistent with California Water Code section 13263(b). Any further use of the assimilative capacity would not The Discharger currently uses chlorine for disinfection and has reported that it uses sodium be consistent with Resolution 68-16. Compliance with these requirements will result in the use of best hypochlorite for maintenance. Chlorine is extremely toxic to aquatic organisms. The Discharger uses practicable treatment or control of the discharge. The impact on existing water quality will be a sulfur dioxide process to dechlorinate the effluent,but will discontinue this with the installation of insignificant. The total allowable discharge to surface water of 9.87 mgd has been increased from 6.95 the UV disinfection system. Because of the existing chlorine use and the future use of hypochlorite mgd from the previous Order. The discharge is consistent with Resolution 68-16 and 40 CFR section solutions without effluent dechlorination,there is reasonable potential for chlorine to be discharged at 131.12 because this Order requires the discharger to meet requirements that will result in best toxic concentrations. The Basin Plan contains a narrative toxicity objective.Consistent with 40 CFR practicable treatment or control to assure that pollution or nuisance will not occur prior to allowing 122.44(d),it is appropriate to use the USEPA ambient water quality criteria for chlorine for protection flows to increase. of freshwater aquatic life of 1 I ug/1 as a 4-day average(chronic)concentration,and 19 ug/1 as a 1-hour